The sinus node is known as the heart's natural “pacemaker”. The sinoatrial node is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava. Impulses originating at the sinoatrial node conduct via myocardial tissue toward the atrial septum and hence toward the left atrium. At the atrial septum, conduction to the ventricles occurs via the atrioventricular node. As the sinoatrial node is located in the right atrium, right atrial contraction occurs prior to left atrial contraction. The right atrium fills the right ventricle and the left atrium fills the left ventricle, which is the main driver for blood circulation through the body. Thus, timing of the left atrial contraction impacts diastolic and systolic function of the left ventricle and hence the left ventricle's ejection volume, efficiency and overall ability to provide blood to the body. Consequently, left ventricular hemodynamics are critical to avert patient symptoms and increase exercise capacity in the heart failure population.
To understand better the relationship between sinoatrial node activity and contraction of the left atrium, an interatrial conduction delay is defined as the time difference between a right atrial event (e.g., an intrinsic event, a paced event, a characteristic of a right atrial electrical activity waveform, etc.) and a left atrial event (e.g., a characteristic of a left atrial electrical activity waveform, etc.). As described herein, various exemplary techniques allow for predicting (or estimating) interatrial conduction delay for paced atrial events. Such techniques are beneficial for clinician guidance and for programming paced and sensed atrioventricular delays. Such techniques may be in the form of a validated model, optionally coded into an implantable device and/or other computing device (e.g., device programmer) via software and/or hardware. Thus, such techniques may be used to suggest or set appropriate AV delays either automatically or on demand. Other exemplary techniques are also disclosed.